Monolithic ceramic capacitor

ABSTRACT

A monolithic ceramic capacitor includes an element body having therein a multilayer portion formed of a plurality of conductor layers and a plurality of ceramic dielectric layers alternately stacked in a thickness direction; and a first outer electrode and a second outer electrode provided on an outer portion of the element body. The element body is divided in the thickness direction into a thickness-direction first outer layer portion, a thickness-direction second outer layer portion, and a thickness-direction inner layer portion located between the thickness-direction first outer layer portion and the thickness-direction second outer layer portion and including the multilayer portion. A first conductor layer and a second conductor layer, which are outermost layers among the plurality of conductor layers, have lower conductor densities than any of conductor densities of the other conductor layers.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a monolithic ceramic capacitor, whichis a type of capacitor element, and which includes a dielectric layermade of a ceramic dielectric material.

2. Description of the Related Art

A capacitor element generally includes an element body, in whichconductor layers and dielectric layers are alternately stacked, and anouter electrode provided on an outer surface of the element body. Amonolithic ceramic capacitor is a type of capacitor element, in whichthe dielectric layers are made of a ceramic dielectric material.

The monolithic ceramic capacitor typically includes therein asubstantially rectangular-parallelepiped-shaped multilayer portion, inwhich a plurality of conductor layers defining inner electrode layersand a plurality of ceramic dielectric layers are alternately denselystacked. The multilayer portion is covered with an outer layer portionmade of ceramic dielectric layers, and an outer layer portion, in whicha relatively small number of conductor layers defining a wiring portionare included in the ceramic dielectric layers. Thus, the above-describedelement body is formed.

To increase the capacity of the monolithic ceramic capacitor, it isrequired to increase the facing area between adjacent conductor layersincluded in the multilayer portion. To increase the facing area, it iseffective to increase the density of the conductor material of theportion in which the conductor layers are arranged, that is, theconductor density (also called inner electrode density). Accordingly,continuity of the conductor layers is increased, the above-describedfacing area is increased, and the capacity of the monolithic ceramiccapacitor is increased.

For example, Japanese Unexamined Patent Application Publication No.2013-12418 discloses a monolithic ceramic capacitor with an increasedcontinuity of the conductor layers.

However, when the continuity of the conductor layers is increased,delamination is likely to occur. The delamination is a separationphenomenon occurring because of a large difference between contractionof the conductor layer and contraction of the ceramic dielectric layer.When thermal history is added, the thermal history acts as a shear forceat a boundary portion between the ceramic dielectric layer and theconductor layer.

In particular, the delamination more likely occurs between themultilayer portion, in which the conductor layers and the ceramicdielectric layers are densely stacked, and the above-described outerlayer portions. The delamination may cause a decrease in reliability ofthe product and a decrease in yield in a manufacturing process.

SUMMARY OF THE PRESENT INVENTION

Accordingly, preferred embodiments of the present invention address theabove-described problems and provide a large-capacity monolithic ceramiccapacitor in which the occurrence of delamination is significantlyreduced or prevented.

According to a preferred embodiment of the present invention, amonolithic ceramic capacitor includes an element body including thereina multilayer portion including a plurality of conductor layers and aplurality of ceramic dielectric layers alternately stacked in athickness direction, and an outer electrode provided on an outer portionof the element body. Outer surfaces of the element body include a firstprincipal surface and a second principal surface opposed in thethickness direction, a first end surface and a second end surfaceopposed in a length direction perpendicular or substantiallyperpendicular to the thickness direction, and a first side surface and asecond side surface opposed in a width direction perpendicular orsubstantially perpendicular to both the thickness direction and thelength direction. The element body is divided in the thickness directioninto a thickness-direction first outer layer portion that includes afirst ceramic dielectric layer and defines the first principal surface,a thickness-direction second outer layer portion that includes a secondceramic dielectric layer and defines the second principal surface, and athickness-direction inner layer portion including the multilayer portionand located between the thickness-direction first outer layer portionand the thickness-direction second outer layer portion. Among theplurality of conductor layers included in the thickness-direction innerlayer portion, a first conductor layer arranged at a position closest tothe first principal surface is provided at a position adjacent to thefirst ceramic dielectric layer of the thickness-direction first outerlayer portion. Among the plurality of conductor layers included in thethickness-direction inner layer portion, a second conductor layerarranged at a position closest to the second principal surface isprovided at a position adjacent to the second ceramic dielectric layerof the thickness-direction second outer layer portion. A conductordensity of the first conductor layer and a conductor density of thesecond conductor layer are lower than any of conductor densities of theother conductor layers located between the first conductor layer and thesecond conductor layer.

In the monolithic ceramic capacitor according to the above-describedpreferred embodiment of the present invention, the first conductor layerand the second conductor layer may include a plurality of fine throughholes penetrating through the first conductor layer and the secondconductor layer in the thickness direction. In this case, the pluralityof through holes may preferably be filled with a ceramic dielectricmaterial.

In the monolithic ceramic capacitor according to the above-describedpreferred embodiments of the present invention, the outer electrode mayinclude a first outer electrode provided to cover the first end surface,and a second outer electrode provided to cover the second end surface.In this case, one portion of the plurality of conductor layers maypreferably be connected with the first outer electrode through a firstwiring portion extending from the multilayer portion toward the firstend surface side, and another portion of the plurality of conductorlayers may be preferably connected with the second outer electrodethrough a second wiring portion extending from the multilayer portiontoward the second end surface side.

In the monolithic ceramic capacitor according to the above-describedpreferred embodiments of the present invention, the element body may bedivided in the length direction into a length-direction first outerlayer portion that includes portions of the conductor layer and theceramic dielectric layer corresponding to the first wiring portion anddefines the first end surface, a length-direction second outer layerportion that includes portions of the conductor layer and the ceramicdielectric layer corresponding to the second wiring portion and definesthe second end surface, and a length-direction inner layer portion thatincludes the multilayer portion and is located between thelength-direction first outer layer portion and the length-directionsecond outer layer portion. In this case, a conductor density in alength-direction first end portion region located at the first endsurface side in the multilayer portion, and a conductor density in alength-direction second end portion region located at the second endsurface side in the multilayer portion may preferably be lower than aconductor density in a length-direction center portion region located atthe center in the length direction in the multilayer portion.

In the monolithic ceramic capacitor according to the above-describedpreferred embodiments of the present invention, a portion of theconductor layer connected with the second outer electrode and includedin the length-direction first end portion region among the plurality ofconductor layers, and a portion of the conductor layer connected withthe first outer electrode and included in the length-direction secondend portion region among the plurality of conductor layers may include aplurality of fine through holes penetrating through the portions of theconductor layers in the thickness direction. In this case, the pluralityof through holes may preferably be filled with the ceramic dielectricmaterial.

In the monolithic ceramic capacitor according to the above-describedpreferred embodiments of the present invention, the element body may bedivided in the width direction into a width-direction first outer layerportion that includes the ceramic dielectric layer and defines the firstside surface, a width-direction second outer layer portion that includesthe ceramic dielectric layer and defines the second side surface, and awidth-direction inner layer portion that includes the multilayer portionand is located between the width-direction first outer layer portion andthe width-direction second outer layer portion. In this case, aconductor density in a width-direction first end portion region locatedat the first side surface side in the multilayer portion, and aconductor density in a width-direction second end portion region locatedat the second side surface side in the multilayer portion may preferablybe lower than a conductor density in a width-direction center portionregion located at the center in the width direction in the multilayerportion.

In the monolithic ceramic capacitor according to the above-describedpreferred embodiments of the present invention, portions included in thewidth-direction first end portion region and the width-direction secondend portion region among the plurality of conductor layers may include aplurality of fine through holes penetrating through the conductor layersin the thickness direction. In this case, the plurality of through holesmay preferably be filled with the ceramic dielectric material.

In the monolithic ceramic capacitor according to the above-describedpreferred embodiments of the present invention, the first conductorlayer and the second conductor layer may be floating conductor layersnot connected to the outer electrode.

With various preferred embodiments of the present invention,large-capacity monolithic ceramic capacitors that significantly reducesor prevents the occurrence of delamination are provided.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a brief perspective view of a monolithic ceramic capacitoraccording to a first preferred embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view taken along line II-II inFIG. 1.

FIG. 3 is a schematic cross-sectional view taken along line III-III inFIG. 1.

FIG. 4 is an enlarged view of region IV in FIG. 2.

FIG. 5 is an exploded view showing a multilayer structure of an elementbody included in the monolithic ceramic capacitor shown in FIG. 1.

FIG. 6 is an illustration showing a manufacturing flow of the monolithicceramic capacitor shown in FIG. 1.

FIG. 7 is a schematic cross-sectional view of a monolithic ceramiccapacitor according to a modification based on the first preferredembodiment of the present invention.

FIG. 8 is a schematic cross-sectional view of a monolithic ceramiccapacitor according to a second preferred embodiment of the presentinvention.

FIG. 9 is an enlarged view of region IX in FIG. 8.

FIG. 10 is an enlarged view of region X in FIG. 8.

FIG. 11 is an exploded view showing a multilayer structure of an elementbody included in the monolithic ceramic capacitor shown in FIG. 8.

FIG. 12 is a schematic cross-sectional view of a monolithic ceramiccapacitor according to a third preferred embodiment of the presentinvention.

FIG. 13 is an enlarged view of region XIII in FIG. 12;

FIG. 14 is an enlarged view of region XIV in FIG. 12.

FIG. 15 is an exploded view showing a multilayer structure of an elementbody included in the monolithic ceramic capacitor shown in FIG. 12.

FIG. 16 is an exploded view showing a multilayer structure of an elementbody included in a monolithic ceramic capacitor according to a fourthpreferred embodiment of the present invention.

FIG. 17 is an exploded view showing a multilayer structure of an elementbody included in a monolithic ceramic capacitor according to a fifthpreferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described belowin detail with reference to the drawings. In the following preferredembodiments, the same reference sign is applied to the same or commonportion in the drawings, and the description is not repeated.

First Preferred Embodiment

FIG. 1 is a schematic perspective view of a monolithic ceramic capacitoraccording to a first preferred embodiment of the present invention.Also, FIGS. 2 and 3 are schematic cross-sectional views taken along lineII-II and line III-III in FIG. 1. FIG. 4 is an enlarged view of regionIV in FIG. 2. A configuration of a monolithic ceramic capacitor 1Aaccording to this preferred embodiment is described with reference toFIGS. 1 to 4.

As shown in FIGS. 1 to 3, the monolithic ceramic capacitor 1A is anelectronic component having a rectangular or substantially rectangularparallelepiped shape, and includes an element body 2, and a first outerelectrode 5 a and a second outer electrode 5 b defining a pair of outerelectrodes.

As shown in FIGS. 2 and 3, the element body 2 has a rectangular orsubstantially rectangular parallelepiped shape, and includes ceramicdielectric layers 3 and inner electrode layers 4 defining and serving asconductor layers alternately stacked in a predetermined direction. Theceramic dielectric layers 3 are preferably made of a ceramic dielectricmaterial including, for example, barium titanate as the mainconstituent. Also, the ceramic dielectric layers 3 may include a Mncompound, a Mg compound, a Si compound, a Co compound, a Ni compound, arare-earth compound, and other suitable compounds, as a sub-constituentof ceramic powder serving as a raw material of a ceramic green sheet(described later); and Al, Si, etc., as a sintering aid. In contrast,the inner electrode layers 4 are preferably made of a base metalmaterial, such as Ni or Cu, for example.

The element body 2 is preferably manufactured by preparing a pluralityof raw-material sheets, each of which is formed by printing a conductivepattern that becomes the inner electrode layer 4 on a surface of aceramic green sheet that becomes the ceramic dielectric layer 3;manufacturing a mother block by stacking and press-bonding the pluralityof raw-material sheets; individualizing the mother block into aplurality of multilayer chips by dividing the mother block; and thenfiring the multilayer chips.

The material of the ceramic dielectric layers 3 is not limited to theceramic dielectric material containing the above-described bariumtitanate as the main constituent, and other ceramic dielectric materialwith a high dielectric constant, for example, a material containingCaZrO₃, CaTiO₃, SrTiO₃, or other suitable material as the mainconstituent, may be used as the material. Also, the material of theinner electrode layers 4 is not limited to the above-described basemetal material, and other conductor material may be used as the materialof the inner electrode layers 4.

As shown in FIGS. 1 and 2, the first outer electrode 5 a and the secondouter electrode 5 b are separated from each other so as to cover theouter surfaces located at both end portions in the predetermineddirection of the element body 2. The first outer electrode 5 a and thesecond outer electrode 5 b are made of conductive films.

The first outer electrode 5 a and the second outer electrode 5 b arepreferably made of multilayer films each including, for example, asintered metal layer and a plated layer. For example, the sintered metallayer is preferably formed by sintering conductor paste, such as Cu, Ni,Ag, Pd, an Ag—Pd alloy, or Au, or conductive resin paste containingmetal powder made of any of these materials. For example, the platedlayer preferably includes a Ni plated layer and a Sn plated layercovering the Ni plated layer. Alternatively, the plated layer may be aCu plated layer or an Au plated layer. Also, the first outer electrode 5a and the second outer electrode 5 b may include only the plated films.

As shown in FIG. 2, one of a pair of the adjacent inner electrode layers4 with the ceramic dielectric layer 3 interposed therebetween in a stackdirection is connected with the first outer electrode 5 a through afirst wiring portion 4 c 1 in the monolithic ceramic capacitor 1A. Theother of the pair of adjacent inner electrode layers 4 with the ceramicdielectric layer 3 interposed therebetween in the stack direction isconnected with the second outer electrode 5 b through a second wiringportion 4 c 2 in the monolithic ceramic capacitor 1A. Accordingly, aplurality of capacitor elements are electrically connected in parallelbetween the first outer electrode 5 a and the second outer electrode 5b.

As shown in FIGS. 2 and 3, in the monolithic ceramic capacitor 1Aaccording to this preferred embodiment, a portion of the above-describedplurality of inner electrode layers 4 excluding the first wiring portion4 c 1 and the second wiring portion 4 c 2 is an area that determines thecapacity of the monolithic ceramic capacitor 1A (so-called effectiveregion). A portion including the portion of the plurality of innerelectrode layers 4 that determines the capacity and the ceramicdielectric layers 3 interposed among the inner electrode layers 4defines a multilayer portion 9, in which the ceramic dielectric layers 3and the inner electrode layers 4 are densely stacked in a thicknessdirection.

With reference to FIGS. 1 to 3, for terms expressing the directions ofthe monolithic ceramic capacitor 1A, the direction in which the ceramicdielectric layers 3 and the inner electrode layers 4 are stacked isdefined as a thickness direction T, the direction in which the firstouter electrode 5 a and the second outer electrode 5 b are arranged isdefined as a length direction L, and the direction perpendicular orsubstantially perpendicular to both the thickness direction T and thelength direction L is defined as a width direction W. These terms areused in the following description.

Also, with reference to FIGS. 2 and 3, among the six outer surfaces ofthe rectangular or substantially rectangular-parallelepiped-shapedelement body 2, a pair of opposite outer surfaces arranged in thethickness direction T are respectively defined as a first principalsurface 2 a 1 and a second principal surface 2 a 2, a pair of oppositeouter surfaces arranged in the length direction L are respectivelydefined as a first end surface 2 b 1 and a second end surface 2 b 2, anda pair of opposite outer surfaces arranged in the width direction W arerespectively defined as a first side surface 2 c 1 and a second sidesurface 2 c 2. These terms are used in the following description.

As shown in FIGS. 1 to 3, the monolithic ceramic capacitor 1A accordingto this preferred embodiment preferably has a rectangular orsubstantially rectangular-parallelepiped shape configured such that theoutside dimension in the length direction L is the longest dimension.The representative values of the outside dimension in the lengthdirection L and the outside dimension in the width direction W (theoutside dimension in the thickness direction T is generally equivalentto the outside dimension in the width direction W) of the monolithicceramic capacitor 1A may preferably be, for example, about 3.2 mm×about1.6 mm, about 2.0 mm×about 1.25 mm, about 1.6 mm×about 0.8 mm, about 1.0mm×about 0.5 mm, about 0.8 mm×about 0.4 mm, about 0.6 mm×about 0.3 mm,about 0.4 mm×about 0.2 mm, and about 0.2 mm×about 0.1 mm.

As shown in FIGS. 2 and 3, the element body 2 is divided into athickness-direction inner layer portion 6 a, a thickness-direction firstouter layer portion 6 b 1, and a thickness-direction second outer layerportion 6 b 2 in the thickness direction T.

The thickness-direction inner layer portion 6 a includes theabove-described multilayer portion 9, and includes the ceramicdielectric layers 3 and the inner electrode layers 4. Among theselayers, the inner electrode layers 4 of the thickness-direction innerlayer portion 6 a include a portion of the inner electrode layer 4included in the multilayer portion 9, a portion of the inner electrodelayer 4 extending from one portion of the portion of the inner electrodelayer 4 included in the multilayer portion 9 toward the first endsurface 2 b 1 side and defining the first wiring portion 4 c 1 connectedwith the first outer electrode 5 a, and a portion of the inner electrodelayer 4 extending from another portion of the portion of the innerelectrode layer 4 included in the multilayer portion 9 toward the secondend surface 2 b 2 side and defining the second wiring portion 4 c 2connected with the second outer electrode 5 b.

The thickness-direction first outer layer portion 6 b 1 includes theceramic dielectric layer 3, and does not include the inner electrodelayer 4. The thickness-direction first outer layer portion 6 b 1 coversa surface of the thickness-direction inner layer portion 6 a at the sideat which the first principal surface 2 a 1 is located. Thus, thethickness-direction first outer layer portion 6 b 1 determines the firstprincipal surface 2 a 1 of the element body 2.

The thickness-direction second outer layer portion 6 b 2 includes theceramic dielectric layer 3, and does not include the inner electrodelayer 4. The thickness-direction second outer layer portion 6 b 2 coversa surface of the thickness-direction inner layer portion 6 a at the sideat which the second principal surface 2 a 2 is located. Thus, thethickness-direction second outer layer portion 6 b 2 determines thesecond principal surface 2 a 2 of the element body 2.

With this configuration, the thickness-direction inner layer portion 6 ais arranged between the thickness-direction first outer layer portion 6b 1 and the thickness-direction second outer layer portion 6 b 2 in thethickness direction T. Among the inner electrode layers 4 included inthe thickness-direction inner layer portion 6 a, a first outermost layer4 a defining a first conductor layer arranged at a position closest tothe first principal surface 2 a 1 side is provided at a positionadjacent to the ceramic dielectric layer 3 of the above-describedthickness-direction first outer layer portion 6 b 1. Among the innerelectrode layers 4 included in the thickness-direction inner layerportion 6 a, a second outermost layer 4 b defining a second conductorlayer arranged at a position closest to the second principal surface 2 a2 side is provided at a position adjacent to the ceramic dielectriclayer 3 of the above-described thickness-direction second outer layerportion 6 b 2.

Also, as shown in FIG. 2, the element body 2 is divided into alength-direction inner layer portion 7 a, a length-direction first outerlayer portion 7 b 1, and a length-direction second outer layer portion 7b 2 in the length direction L.

The length-direction inner layer portion 7 a includes theabove-described multilayer portion 9, and includes the plurality ofceramic dielectric layers 3 and the plurality of inner electrode layers4. Among these layers, the plurality of inner electrode layers 4 of thelength-direction inner layer portion 7 a include only a portion of theinner electrode layers 4 included in the multilayer portion 9.

The length-direction first outer layer portion 7 b 1 includes portionsof the inner electrode layers 4 and the ceramic dielectric layers 3 ofthe first wiring portion 4 c 1. The length-direction first outer layerportion 7 b 1 covers a surface of the length-direction inner layerportion 7 a at the side at which the first end surface 2 b 1 is located.Thus, the length-direction first outer layer portion 7 b 1 determinesthe first end surface 2 b 1 of the element body 2.

The length-direction second outer layer portion 7 b 2 includes portionsof the inner electrode layers 4 and the ceramic dielectric layers 3 ofthe second wiring portion 4 c 2. The length-direction second outer layerportion 7 b 2 covers a surface of the length-direction inner layerportion 7 a at the side at which the second end surface 2 b 2 islocated. Thus, the length-direction second outer layer portion 7 b 2determines the second end surface 2 b 2 of the element body 2.

With this configuration, the length-direction inner layer portion 7 a isarranged between the length-direction first outer layer portion 7 b 1and the length-direction second outer layer portion 7 b 2 in the lengthdirection L.

Further, as shown in FIG. 3, the element body 2 is divided into awidth-direction inner layer portion 8 a, a width-direction first outerlayer portion 8 b 1, and a width-direction second outer layer portion 8b 2 in the width direction W.

The width-direction inner layer portion 8 a includes the above-describedmultilayer portion 9, and includes the plurality of ceramic dielectriclayers 3 and the plurality of inner electrode layers 4. Among theselayers, the inner electrode layers 4 of the width-direction inner layerportion 8 a include a portion of the inner electrode layers 4 includedin the multilayer portion 9, a portion of the inner electrode layers 4of the first wiring portion 4 c 1, and a portion of the inner electrodelayers 4 of the second wiring portion 4 c 2.

The width-direction first outer layer portion 8 b 1 includes the ceramicdielectric layer 3, and does not include the inner electrode layer 4.The width-direction first outer layer portion 8 b 1 covers a surface ofthe width-direction inner layer portion 8 a at the side at which thefirst side surface 2 c 1 is located, and thus, the width-direction firstouter layer portion 8 b 1 determines the first side surface 2 c 1 of theelement body 2.

The width-direction second outer layer portion 8 b 2 includes theceramic dielectric layer 3, and does not include the inner electrodelayer 4. The width-direction second outer layer portion 8 b 2 covers asurface of the width-direction inner layer portion 8 a at the side atwhich the second side surface 2 c 2 is located, and thus, thewidth-direction second outer layer portion 8 b 2 determines the secondside surface 2 c 2 of the element body 2.

With this configuration, the width-direction inner layer portion 8 a isarranged between the width-direction first outer layer portion 8 b 1 andthe width-direction second outer layer portion 8 b 2 in the widthdirection W.

As described above, in the monolithic ceramic capacitor 1A according tothis preferred embodiment, the element body 2 includes the rectangularor substantially rectangular-parallelepiped-shaped multilayer portion 9,in which the plurality of inner electrode layers 4 and the plurality ofceramic dielectric layers 3 are alternately densely stacked, and theelement body 2 is configured such that the outer layer portions definedby the ceramic dielectric layers 3, that is, the thickness-directionfirst outer layer portion 6 b 1, the thickness-direction second outerlayer portion 6 b 2, the width-direction first outer layer portion 8 b1, and the width-direction second outer layer portion 8 b 2, and theouter layer portions defined by the ceramic dielectric layers 3 and therelatively small number of inner electrode layers 4 defining and servingas the wiring portion included in the ceramic dielectric layers 3, thatis, the length-direction first outer layer portion 7 b 1 and thelength-direction second outer layer portion 7 b 2, cover the multilayerportion 9.

In the monolithic ceramic capacitor 1A according to this preferredembodiment, the conductor density of the first outermost layer 4 a andthe conductor density of the second outermost layer 4 b are preferablylower than the conductor density of any of the other inner electrodelayers 4 located between the first outermost layer 4 a and the secondoutermost layer 4 b. With this configuration, the capacity of themonolithic ceramic capacitor is increased while the occurrence ofdelamination is effectively reduced. The details are described below.

As shown in FIG. 4, the first outermost layer 4 a is defined by a filmof a conductor material having a predetermined thickness. The firstoutermost layer 4 a includes a plurality of fine through holespenetrating through the first outermost layer 4 a in the thicknessdirection T. The through holes are filled with a filling portion 3 amade of a ceramic dielectric material. Thus, the first outermost layer 4a is discontinuous in any cross-section parallel or substantiallyparallel to the thickness direction T. Accordingly, the conductordensity is relatively low. Although not shown, the second outermostlayer 4 b has a configuration the same or substantially the same as thatof the first outermost layer 4 a.

As described above, since the conductor densities of the first outermostlayer 4 a and the second outermost layer 4 b are relatively low, theabove-described filling portions 3 a made of the ceramic dielectricmaterial function as a type of support, i.e., anchor, that couplesportions of the ceramic dielectric layers 3 sandwiching each of thefirst outermost layer 4 a and the second outermost layer 4 b. Thus, ahigh fixing force between each of the first outermost layer 4 a and thesecond outermost layer 4 b and the ceramic dielectric layer 3 located onan outer side portion of the corresponding outermost layer ismaintained. Thus, the occurrence of delamination is effectively reducedat a boundary portion between the thickness-direction inner layerportion 6 a and the thickness-direction first outer layer portion 6 b 1,and at a boundary portion between the thickness-direction inner layerportion 6 a and the thickness-direction second outer layer portion 6 b2.

In contrast, although the other inner electrode layers located betweenthe first outermost layer 4 a and the second outermost layer 4 b areeach defined by a film of a conductor material having a predeterminedthickness, such an inner electrode layer 4 has relatively highcontinuity in any cross-section parallel or substantially parallel tothe thickness direction T. Accordingly, the conductor density isrelatively high.

As described above, since the conductor density of the other innerelectrode layers 4 located between the first outermost layer 4 a and thesecond outermost layer 4 b is relatively high, the facing area betweenadjacent inner electrode layers 4 among these inner electrode layers 4is increased, and thus, the capacity is increased.

Accordingly, as long as the conductor densities of the first outermostlayer 4 a and the second outermost layer 4 b are lower than theconductor densities of the inner electrode layers 4 arranged between thefirst outermost layer 4 a and the second outermost layer 4 b, thecapacity of the monolithic ceramic capacitor is increased while theoccurrence of delamination is effectively reduced. In many cases,several hundreds of the inner electrode layers 4 are stacked. Thus, adecrease in capacity caused by decreasing the conductor densities of thefirst outermost layer 4 a and the second outermost layer 4 b isnegligible as compared to the effect of reducing the occurrence ofdelamination.

Preferably, the conductor density of the first outermost layer 4 a andthe conductor density of the second outermost layer 4 b are lower thanthe conductor density of the inner electrode layer 4 located between thefirst outermost layer 4 a and the second outermost layer 4 b preferablyby, for example, about 5% to about 10%. For example, if the conductordensity of the inner electrode layer 4 located between the firstoutermost layer 4 a and the second outermost layer 4 b preferably isabout 70% to about 90%, the conductor density of the first outermostlayer 4 a and the conductor density of the second outermost layer 4 bmay preferably be about 60% to about 85%.

The conductor density of the first outermost layer 4 a, the conductordensity of the second outermost layer 4 b, and the conductor density ofthe inner electrode layer 4 located between the first outermost layer 4a and the second outermost layer 4 b can be measured, for example, bythe following process.

First, the monolithic ceramic capacitor to be measured is sealed withsealing resin, and the monolithic ceramic capacitor with the sealingresin is ground. The grinding is advanced in the thickness direction Tof the monolithic ceramic capacitor. Then, the grinding is stopped at atiming when the first outermost layer is exposed, at a timing when theinner electrode layer located in a center portion in the thicknessdirection T is exposed, and at a timing when the second outermost layeris exposed, and images of cross-sections at the timings at which thegrinding is stopped are captured. The images of the cross-sections arecaptured by using an electron microscope (for example, scanning electronmicroscope (SEM)), and the magnification is preferably in a range fromabout 500 times to about 1000 times. Then, an image in a range to bemeasured is extracted from each captured image, binarization processingis executed on the extracted image, the area of a portion correspondingto the conductor material and the area of a portion not corresponding tothe conductor material are measured, and the conductor density of eachlayer is calculated based on the measured areas. The calculatedconductor densities of respective layers are compared, and a differencein density of each layer can be specified.

An example of a non-limiting method of causing the conductor densitiesof the first outermost layer 4 a and the second outermost layer 4 b tobe lower than the conductor density of any of the inner electrode layers4 located between the first outermost layer 4 a and the second outermostlayer 4 b is described as follows. FIG. 5 is an exploded view showing amultilayer structure of the element body included in the monolithicceramic capacitor shown in FIG. 1.

As shown in FIG. 5, the element body 2 is manufactured using a materialsheet group 10A as a material including a plurality of material sheets11A, 11B1, 11B2, 11C1, and 11C2 with different configurations. To bemore specific, the element body is manufactured by stacking theplurality of material sheets 11A, 11B1, 11B2, 11C1, and 11C2 with thedifferent configurations in a predetermined order, press-bonding thematerial sheets, and firing the material sheets.

The material sheet 11A is formed of only a ceramic base 12 and does notinclude a conductive pattern on its surface. The material sheet 11Abecomes the ceramic dielectric layer 3 of a portion that defines thethickness-direction first outer layer portion 6 b 1 or thethickness-direction second outer layer portion 6 b 2 after firing.

The material sheets 11B1 and 11B2 each include a conductive pattern 13 ahaving a predetermined shape formed on a surface of a ceramic base 12.The conductive pattern 13 a of the material sheets 11B1 and 11B2 becomesa portion of the inner electrode layer 4 excluding the first outermostlayer 4 a and the second outermost layer 4 b after firing. Also, theceramic base 12 of each of the material sheets 11B1 and 11B2 becomes aportion of the ceramic dielectric layer 3 that defines thethickness-direction inner layer portion 6 a after firing.

The material sheets 11C1 and 11C2 each include a conductive pattern 13 bhaving a predetermined shape formed on a surface of a ceramic base 12.The conductive patterns 13 b of the material sheets 11C1 and 11C2 becomethe first outermost layer 4 a and the second outermost layer 4 b amongthe inner electrode layers 4 after firing. Also, the ceramic base 12 ofthe material sheet 11C1 becomes a portion of the ceramic dielectriclayer 3 that defines the thickness-direction inner layer portion 6 aafter firing. The ceramic base 12 of the material sheet 11C2 becomes aportion of the ceramic dielectric layer 3 that defines thethickness-direction second outer layer portion 6 b 2 after firing.

Each of the above-described conductive patterns 13 a and 13 b can beformed by applying the conductor paste to the surface of the ceramicbase 12, for example, by screen printing or gravure printing. In thiscase, for the conductive pattern 13 a that becomes the portion of theinner electrode layer 4 excluding the first outermost layer 4 a and thesecond outermost layer 4 b after firing, the thickness of the conductorpaste to be applied is relatively large. For the conductive pattern 13 bthat becomes the first outermost layer 4 a and the second outermostlayer 4 b among the inner electrode layers 4 after firing, the thicknessof the conductor paste to be applied is relatively small.

Accordingly, the conductor densities of the first outermost layer 4 aand the second outermost layer 4 b after firing are lower than theconductor density of any of the inner electrode layers 4 located betweenthe first outermost layer 4 a and the second outermost layer 4 b. Manyfilling portions 3 a (described above) are provided in the firstoutermost layer 4 a and the second outermost layer 4 b.

As a method of changing the thickness of the conductor paste to beapplied to the ceramic base 12, in the case of screen printing, theamount of the conductor paste to be transferred on the ceramic base 12can be controlled by adjusting the size of a mesh provided on a screenprinting plate (that is, the size of holes). In the case of gravureprinting, the amount of the conductor paste to be transferred on theceramic base 12 can be controlled by adjusting the size of a pattern ofa gravure plate and adjusting the viscosity of the conductor paste.

FIG. 6 is an illustration showing a non-limiting example of amanufacturing flow of the monolithic ceramic capacitor shown in FIG. 1.Next, a manufacturing flow of the monolithic ceramic capacitor 1Aaccording to this preferred embodiment is described with reference toFIG. 6. The manufacturing flow of the monolithic ceramic capacitor 1Adescribed below is manufacturing a mother block by collectivelyexecuting processing until an intermediate phase of the manufacturingprocess, then dividing the mother block into individual chips, andfurther executing processing on the individual chips, so that aplurality of the monolithic ceramic capacitors 1A are manufacturedsimultaneously in a large quantity.

As shown in FIG. 6, when the above-described monolithic ceramiccapacitor 1A is manufactured, first, ceramic slurry is prepared (stepS1). More specifically, ceramic powder, a binder, a solvent, and othersuitable ingredients, are mixed by a predetermined formulation ratio toproduce the ceramic slurry.

Then, a ceramic green sheet is formed (step S2). More specifically, theceramic green sheet is manufactured by molding the ceramic slurry in asubstantially sheet shaped configuration on a carrier film using, forexample, a die coater, a gravure coater, a microgravure coater, or othersuitable coater.

Then, a raw-material sheet is formed (step S3). More specifically, theraw-material sheet with a predetermined conductive pattern provided onthe ceramic green sheet is formed by printing the conductor paste on theceramic green sheet by screen printing or gravure printing so that theconductor paste has a predetermined pattern, for example.

The raw-material sheet to be manufactured has a layout such that aplurality of material sheets having the same or substantially the sameshape are arranged in a matrix in plan on a material sheet for each ofthe material sheets 11B1, 11B2, 11C1, and 11C2 shown in FIG. 5 as aunit.

Since the material sheet 11B1 and the material sheet 11B2 have the sameor substantially the same shape, raw-material sheets including thematerial sheet 11B1 and the material sheet 11B2 may utilize raw-materialsheets having the same or substantially the same conductive pattern. Bystacking the raw-material sheets having the same or substantially thesame conductive pattern so as to be shifted by a half pitch in astacking step of the raw-material sheets (described later), themultilayer structure of the material sheets 11B1 and 11B2 shown in FIG.5 can be obtained.

Also, since the material sheet 11C1 and the material sheet 11C2 have thesame or substantially the same shape, raw-material sheets including thematerial sheet 11C1 and the material sheet 11C2 may utilize raw-materialsheets having the same or substantially the same conductive pattern. Bystacking the raw-material sheets having the same or substantially thesame conductive pattern so as to be shifted by a half pitch in astacking step of the raw-material sheets (described later), themultilayer structure of the material sheets 11C1 and 11C2 shown in FIG.6 can be obtained.

On each of the raw-material sheets including the material sheets 11B1and 11B2, the conductive pattern 13 a is preferably formed with arelatively large thickness as described above. On each of theraw-material sheets including the material sheets 11C1 and 11C2, theconductive pattern 13 b is preferably formed with a relatively smallthickness as described above.

In addition to the raw-material sheets having the above-describedconductive patterns 13 a and 13 b, raw-material sheets formed of onlyceramic green sheets manufactured without the step S3 are also prepared.

Then, the raw-material sheets are stacked (step S4). More specifically,the above-described plurality of raw-material sheets are stacked under apredetermined rule, and hence the raw-material sheets are arranged sothat the above-described unit has a multilayer structure as shown inFIG. 5 in the stack direction in the raw-material sheet group afterstacking.

Then, the raw-material sheet group is press-bonded (step S5). Morespecifically, the raw-material sheet group is pressed in the stackingdirection by using, for example, hydrostatic pressing, and thus, theraw-material sheet group is press-bonded. Accordingly, theabove-described mother block is manufactured.

Then, the mother block is divided (step S6). More specifically,press-cutting or dicing is performed such that the mother block isdivided into a matrix. Accordingly, the chips are cut. The cut chipseach have the multilayer structure shown in FIG. 5.

Then, the chip is fired (step S7). More specifically, the cut chip isheated at a predetermined temperature such that the ceramic dielectricmaterial and the conductor material are sintered. If it is assumed thatthe chip is sintered in an oxidized atmosphere, more of the fillingportions 3 a are formed in the above-described first outermost layer 4 aand second outermost layer 4 b. Thus, the occurrence of delamination isfurther reliably reduced.

Then, the chip is ground by barrel grinding (step S8). Morespecifically, the chip after sintering is sealed in a small box called abarrel with medium balls with a higher hardness than the hardness of theceramic material, the barrel is rotated, and the chip is ground.Accordingly, the outer surfaces (in particular, an edge portion and acorner portion) of the chip are rounded. Thus, the above-describedelement body 2 is formed.

Then, an outer electrode is formed (step S9). More specifically, metalfilms are formed by applying the conductor paste on an end portion of aportion including the first end surface 2 b 1 and an end portion of aportion including the second end surface 2 b 2 of the element body 2,the formed metal films are sintered, and then Ni plating and Sn platingare successively applied to the metal films. Accordingly, the firstouter electrode 5 a and the second outer electrode 5 b are formed on theouter surfaces of the element body 2.

By performing the above-described series of steps, the manufacturing ofthe monolithic ceramic capacitor 1A having the structure shown in FIGS.1 to 3 is completed.

As described above, in the monolithic ceramic capacitor 1A according tothis preferred embodiment, as long as the conductor densities of thefirst outermost layer 4 a and the second outermost layer 4 b are lowerthan the conductor density of any of the inner electrode layers 4located between the first outermost layer 4 a and the second outermostlayer 4 b, the capacity of the monolithic ceramic capacitor is increasedwhile the occurrence of delamination is effectively reduced.Accordingly, the reliability of the product is increased, and the yieldof the manufacturing process is prevented from begin decreased.

FIG. 7 is a schematic cross-sectional view of a monolithic ceramiccapacitor according to a modification based on this preferredembodiment. Next, a monolithic ceramic capacitor 1B according to themodification based on this preferred embodiment is described withreference to FIG. 7.

As shown in FIG. 7, the monolithic ceramic capacitor 1B according tothis modification differs from the monolithic ceramic capacitor 1Aaccording to the above-described preferred embodiment in that the firstoutermost layer 4 a and the second outermost layer 4 b are not connectedwith the first outer electrode 5 a or the second outer electrode 5 b,and both the first outermost layer 4 a and the second outermost layer 4b are defined by stray (floating) conductor layers.

Even with this configuration, similarly to the monolithic ceramiccapacitor 1A according to the above-described preferred embodiment, aslong as the conductor densities of the first outermost layer 4 a and thesecond outermost layer 4 b are lower than the conductor density of anyof the inner electrode layers 4 located between the first outermostlayer 4 a and the second outermost layer 4 b, the capacity of themonolithic ceramic capacitor is increased while the occurrence ofdelamination is effectively reduced. As described above, in many cases,since several hundreds of the inner electrode layers 4 are stacked, adecrease in capacity caused when the first outermost layer 4 a and thesecond outermost layer 4 b are each defined by the stray (floating)conductor layer is negligible as compared to the effect of reducing theoccurrence of delamination.

Second Preferred Embodiment

FIG. 8 is a schematic cross-sectional view of a monolithic ceramiccapacitor according to a second preferred embodiment of the presentinvention. Also, FIGS. 9 and 10 are enlarged views of region IX andregion X shown in FIG. 8. First, a configuration of a monolithic ceramiccapacitor 1C according to this preferred embodiment is described withreference to FIGS. 8 to 10.

As shown in FIGS. 8 to 10, the monolithic ceramic capacitor 1C accordingto this preferred embodiment differs from the monolithic ceramiccapacitor 1A according to the above-described first preferred embodimentin the configuration of the inner electrode layer 4, and morespecifically, in that a portion of the plurality of inner electrodelayers 4 having a lower conductor density than the conductor density ofthe other portion is different from that portion of the monolithicceramic capacitor 1A according to the above-described first preferredembodiment.

In the monolithic ceramic capacitor 1C according to this preferredembodiment, unlike the monolithic ceramic capacitor 1A according to theabove-described first preferred embodiment, the conductor density of thefirst outermost layer 4 a and the conductor density of the secondoutermost layer 4 b are preferably equivalent or substantiallyequivalent to the density of the conductive material in the other innerelectrode layer 4 located between the first outermost layer 4 a and thesecond outermost layer 4 b. However, the conductor densities of allinner electrode layers 4 including the first outermost layer 4 a and thesecond outermost layer 4 b change along in the length direction L.

More specifically, the conductor density of a length-direction first endportion region 9 b 1 located at the first end surface 2 b 1 side in themultilayer portion 9 and the conductor density of a length-directionsecond end portion region 9 b 2 located at the second end surface 2 b 2side in the multilayer portion 9 are lower than the conductor density ofa length-direction center portion region 9 a located at the center inthe length direction L in the multilayer portion 9. With thisconfiguration, the capacity of the monolithic ceramic capacitor isincreased while the occurrence of delamination is effectively reduced.The details are described below.

As shown in FIG. 9, in the length-direction first end portion region 9 b1, the inner electrode layer 4 connected with the second outer electrode5 b among the plurality of inner electrode layers 4 includes a pluralityof fine through holes penetrating through the inner electrode layer 4 inthe thickness direction T, and the through holes are preferably filledwith filling portions 3 a made of a ceramic dielectric material.Accordingly, a portion of the inner electrode layer 4 connected to thesecond outer electrode 5 b and included in the length-direction firstend portion region 9 b 1 is discontinuous in any cross-section parallelor substantially parallel to the thickness direction T, and thus, has arelatively low conductor density.

Also, although not shown, in the length-direction second end portionregion 9 b 2, the inner electrode layer 4 connected with the first outerelectrode 5 a among the plurality of inner electrode layers 4 includes aplurality of fine through holes penetrating through the inner electrodelayer 4 in the thickness direction T, and the through holes arepreferably filled with filling portions 3 a made of a ceramic dielectricmaterial. Accordingly, a portion of the inner electrode layer 4connected to the first outer electrode 5 a and included in thelength-direction second end portion region 9 b 2 is discontinuous in anycross-section parallel or substantially to the thickness direction T,and thus, has a relatively low conductor density.

In this manner, since the conductor density of a portion of the innerelectrode layers 4 in the portions included in the length-directionfirst end portion region 9 b 1 and the length-direction second endportion region 9 b 2 is relatively low, each of the above-describedfilling portions 3 a made of the ceramic dielectric material functionsas a support, i.e., anchor, that couples portions of the ceramicdielectric layers 3 sandwiching the portion of the inner electrode layer4. A high fixing force between the portion of the inner electrode layer4 and the ceramic dielectric layers 3 sandwiching the portion of theinner electrode layer 4 is maintained. The occurrence of delamination,which starts at a boundary portion between the length-direction innerlayer portion 7 a and the length-direction first outer layer portion 7 b1, and a boundary portion between the length-direction inner layerportion 7 a and the length-direction second outer layer portion 7 b 2,is effectively reduced.

The size in the length direction L of the length-direction first endportion region 9 b 1, which is a region including the portion that has alower conductor density than the conductor density of the other portionof the inner electrode layer 4 connected with the second outer electrode5 b, is not particularly limited. However, if the size is determinedsuch that the distance from the end portion at the first end surface 2 b1 side of the inner electrode layer 4 connected with the second outerelectrode 5 b is preferably within a range of about 10 μm, theoccurrence of delamination, which starts at the boundary portion betweenthe length-direction inner layer portion 7 a and the length-directionfirst outer layer portion 7 b 1, is further reliably reduced.

Also, the size in the length direction L of the length-direction secondend portion region 9 b 2, which is a region including the portion thatshould have a lower conductor density than the conductor density of theother portion of the inner electrode layer 4 connected with the firstouter electrode 5 a, is not particularly limited. However, if the sizeis determined such that the distance from the end portion at the secondend surface 2 b 2 side of the inner electrode layer 4 connected with thefirst outer electrode 5 a is preferably within a range of about 10 μm,the occurrence of delamination, which starts at the boundary portionbetween the length-direction inner layer portion 7 a and thelength-direction second outer layer portion 7 b 2, is further reliablyreduced.

In contrast, as shown in FIG. 10, in the length-direction center portionregion 9 a, all of the plurality of inner electrode layers 4 haverelatively high continuity in any cross-section parallel orsubstantially parallel to the thickness direction T. Thus, the conductordensity is relatively high.

In this manner, since the conductor densities of the inner electrodelayers 4 included in the length-direction center portion region 9 a arerelatively high, the facing area between adjacent inner electrode layers4 among the inner electrode layers 4 is increased, and the capacity isincreased.

Since the conductor density in the length-direction first end portionregion 9 b 1 and the conductor density in the length-direction secondend portion region 9 b 2 are lower than the conductor density in thelength-direction center portion region 9 a, the capacity of themonolithic ceramic capacitor is increased while the occurrence ofdelamination is effectively reduced. The size of the length-directionfirst end portion region 9 b 1 and the length-direction second endportion region 9 b 2 may be very small as described above, the decreasein capacity caused when the conductor density of a portion of the innerelectrode layers 4 included in the portions is decreased is almostnegligible as compared to the effect of reducing the occurrence ofdelamination.

Preferably, the conductor density of the portion of the inner electrodelayer 4 connected with the second outer electrode 5 b and included inthe length-direction first end portion region 9 b 1 and the conductordensity of the portion of the inner electrode layer 4 connected with thefirst outer electrode 5 a and included in the length-direction secondend portion region 9 b 2 are lower than the conductor density of theportion of the inner electrode layer 4 included in the length-directioncenter portion region 9 a preferably by, for example, about 5% to about10%. For example, if the conductor density of the portion of the innerelectrode layer 4 included in the length-direction center portion region9 a preferably is about 70% to about 90%, the conductor density of theportion of the inner electrode layer 4 connected with the second outerelectrode 5 b and included in the length-direction first end portionregion 9 b 1 and the conductor density of the portion of the innerelectrode layer 4 connected with the first outer electrode 5 a andincluded in the length-direction second end portion region 9 b 2 maypreferably be about 60% to about 85%, for example.

The conductor density of the portion of the inner electrode layer 4connected with the second outer electrode 5 b and included in thelength-direction first end portion region 9 b 1, the conductor densityof the portion of the inner electrode layer 4 connected with the firstouter electrode 5 a and included in the length-direction second endportion region 9 b 2, and the conductor density of the portion of theinner electrode layer 4 included in the length-direction center portionregion 9 a can be measured by the measuring method using the electronmicroscope described in the aforementioned first preferred embodiment.More specifically, the measurement can be performed by setting thecross-section exposed during grinding at a cross-section including thelength-direction first end portion region 9 b 1, a cross-sectionincluding the length-direction center portion region 9 a, and across-section including the length-direction second end portion region 9b 2, or at a cross-section collectively including the length-directionfirst end portion region 9 b 1, the length-direction center portionregion 9 a, and the length-direction second end portion region 9 b 2.

An example of a non-limiting method of causing the conductor density inthe length-direction first end portion region 9 b 1 and the conductordensity in the length-direction second end portion region 9 b 2 to belower than the conductor density in the length-direction center portionregion 9 a is described below. FIG. 11 is an exploded view showing amultilayer structure of an element body included in the monolithicceramic capacitor shown in FIG. 8.

As shown in FIG. 11, the element body 2 is manufactured using a materialsheet group 10C as a material including a plurality of material sheets11A, 11D1, and 11D2 with different configurations. More specifically,the element body 2 is manufactured by stacking the plurality of materialsheets 11A, 11D1, and 11D2 with the different configurations in apredetermined order, press-bonding the material sheets, and firing thematerial sheets.

The material sheet 11A is formed of only a ceramic base 12 and does notinclude a conductive pattern on its surface. The material sheet 11Abecomes a portion of the ceramic dielectric layer 3 that defines thethickness-direction first outer layer portion 6 b 1 or thethickness-direction second outer layer portion 6 b 2 after firing.

The material sheets 11D1 and 11D2 each include conductive patterns 13 aand 13 b having predetermined shapes provided on a surface of a ceramicbase 12. The conductive pattern 13 a is a conductive pattern of aportion that is included primarily in the length-direction centerportion region 9 a and the first wiring portion 4 c 1 or the secondwiring portion 4 c 2 after firing, and is strip-shaped or substantiallystrip shaped extending in the length direction L. The conductive pattern13 b is a conductive pattern of a portion that is included primarily inthe length-direction first end portion region 9 b 1 or thelength-direction second end portion region 9 b 2 after firing, and islocated at one end portion side of the conductive pattern 13 a so as toextend in the length direction L. Also, the ceramic base 12 of each ofthe material sheets 11D1 and 11D2 becomes the ceramic dielectric layer 3of a portion that defines the thickness-direction inner layer portion 6a or the thickness-direction second outer layer portion 6 b 2 afterfiring.

Similarly to the first preferred embodiment, the above-describedconductive patterns 13 a and 13 b are configured to have differentthicknesses by adjusting the amount of conductor paste to be applied tothe ceramic bases 12. Accordingly, the conductor density in thelength-direction first end portion region 9 b 1 and the conductordensity in the length-direction second end portion region 9 b 2 ispreferably lower than the conductor density in the length-directioncenter portion region 9 a during firing.

As describe above, in the monolithic ceramic capacitor 1C according tothis preferred embodiment, since the conductor density in thelength-direction first end portion region 9 b 1 and the conductordensity in the length-direction second end portion region 9 b 2 arelower than the conductor density in the length-direction center portionregion 9 a, the capacity of the monolithic ceramic capacitor isincreased while the occurrence of delamination is effectively reduced.Accordingly, the reliability of the product is increased, and the yieldof the manufacturing process is prevented from being decreased.

Third Preferred Embodiment

FIG. 12 is a schematic cross-sectional view of a monolithic ceramiccapacitor according to a third preferred embodiment of the presentinvention. FIGS. 13 and 14 are enlarged views of region XIII and regionXIV shown in FIG. 12. A configuration of a monolithic ceramic capacitor1D according to this preferred embodiment is described with reference toFIGS. 12 to 14.

As shown in FIGS. 12 to 14, the monolithic ceramic capacitor 1Daccording to this preferred embodiment differs from the monolithicceramic capacitor 1A according to the above-described first preferredembodiment in the configuration of the inner electrode layer 4, and morespecifically, in that a portion of the plurality of inner electrodelayers 4 having a lower conductor density than the conductor density ofthe other portion is different from that portion of the monolithicceramic capacitor 1A according to the first preferred embodiment.

In the monolithic ceramic capacitor 1D according to this preferredembodiment, unlike the monolithic ceramic capacitor 1A according to theabove-described first preferred embodiment, the conductor density of thefirst outermost layer 4 a and the conductor density of the secondoutermost layer 4 b are preferably equivalent or substantiallyequivalent to the density of the conductive material of the other innerelectrode layer 4 located between the first outermost layer 4 a and thesecond outermost layer 4 b. However, the conductor densities of allinner electrode layers 4 including the first outermost layer 4 a and thesecond outermost layer 4 b change along the width direction W.

More specifically, the conductor density in a width-direction first endportion region 9 d 1 located at the first side surface 2 c 1 in themultilayer portion 9 and the conductor density in a width-directionsecond end portion region 9 d 2 located at the second side surface 2 c 2in the multilayer portion 9 are preferably lower than the conductordensity in a width-direction center portion region 9 c located at thecenter in the width direction W in the multilayer portion 9. With thisconfiguration, the capacity of the monolithic ceramic capacitor isincreased while the occurrence of delamination is effectively reduced.The details are described below.

As shown in FIG. 13, in the width-direction first end portion region 9 d1, the plurality of inner electrode layers 4 include a plurality of finethrough holes penetrating through the inner electrode layers 4 in thethickness direction T, and the through holes are filled with fillingportions 3 a made of a ceramic dielectric material. Thus, a portion ofthe inner electrode layers 4 included in the width-direction first endportion region 9 d 1 is discontinuous in any cross-section parallel orsubstantially parallel to the thickness direction T, the conductordensity is relatively low.

Also, although not shown, in the width-direction second end portionregion 9 d 2, the plurality of inner electrode layers 4 include aplurality of fine through holes penetrating through the inner electrodelayers 4 in the thickness direction T, and the through holes are filledwith filling portions 3 a made of a ceramic dielectric material. Thus, aportion of the inner electrode layers 4 included in the width-directionsecond end portion region 9 d 2 is discontinuous in any cross-sectionparallel or substantially parallel to the thickness direction T, andconductor density is relatively low.

In this manner, since the conductor densities of the portions of theinner electrode layers 4 included in the width-direction first endportion region 9 d 1 and the width-direction second end portion region 9d 2 are relatively low, the above-described filling portion 3 a made ofthe ceramic dielectric material functions as a support, i.e., an anchor,that couples portions of the ceramic dielectric layers 3 sandwiching theportion of the inner electrode layer 4. A high fixing force between theportion of the inner electrode layer 4 and the ceramic dielectric layers3 sandwiching the portion of the inner electrode layer 4 is maintained.The occurrence of delamination, which starts at a boundary portionbetween the width-direction inner layer portion 8 a and thewidth-direction first outer layer portion 8 b 1, and a boundary portionbetween the width-direction inner layer portion 8 a and thewidth-direction second outer layer portion 8 b 2, is effectivelyreduced.

The size in the width direction W of the width-direction first endportion region 9 d 1, which is a region including the portion of theinner electrode layer 4 having a conductor density lower than theconductor density of the other portion, is not particularly limited.However, if the size is determined such that the distance from the endportion at the first side surface 2 c 1 side of the inner electrodelayer 4 is preferably within about 10 μm, for example, the occurrence ofdelamination, which starts at the boundary portion between thewidth-direction inner layer portion 8 a and the width-direction firstouter layer portion 8 b 1, is reliably reduced.

Also, the size in the width direction W of the width-direction secondend portion region 9 d 2, which is a region including the portion of theinner electrode layer 4 having the conductor density lower than theconductor density of the other portion, is not particularly limited.However, if the size is determined such that the distance from the endportion at the second side surface 2 c 2 side of the inner electrodelayer 4 is preferably within about 10 μm, for example, the occurrence ofdelamination, which starts at the boundary portion between thewidth-direction inner layer portion 8 a and the width-direction secondouter layer portion 8 b 2, is reliably reduced.

In contrast, as shown in FIG. 14, in the width-direction center portionregion 9 c, all of the plurality of inner electrode layers 4 haverelatively high continuity in any cross-section parallel orsubstantially parallel to the thickness direction T. Thus, the conductordensity is relatively high.

In this manner, since the conductor density of the inner electrode layer4 included in the width-direction center portion region 9 c isrelatively high, the facing area between the adjacent inner electrodelayers 4 among the inner electrode layers 4 is increased, and thecapacity is increased.

Since the conductor density in the width-direction first end portionregion 9 d 1 and the conductor density in the width-direction second endportion region 9 d 2 are lower than the conductor density in thewidth-direction center portion region 9 c, the capacity of themonolithic ceramic capacitor is increased while the occurrence ofdelamination is effectively reduced. The size of the width-directionfirst end portion region 9 d 1 and the size of the width-directionsecond end portion region 9 d 2 may be very small as described above,the decrease in capacity caused when the conductor density of the innerelectrode layer 4 included in the portion is decreased is almostnegligible as compared to the effect of reducing the occurrence ofdelamination.

Preferably, the conductor density of the portion of the inner electrodelayer 4 included in the width-direction first end portion region 9 d 1and the conductor density of the portion of the inner electrode layer 4included in the width-direction second end portion region 9 d 2 arelower than the conductor density of the portion of the inner electrodelayer 4 included in the width-direction center portion region 9 cpreferably by, for example, about 5% to about 10%. For example, if theconductive density of the portion of the inner electrode layer 4included in the width-direction center portion region 9 c preferably isabout 70% to about 90%, the conductor density of the portion of theinner electrode layer 4 included in the width-direction first endportion region 9 d 1 and the conductor density of the portion of theinner electrode layer 4 included in the width-direction second endportion region 9 d 2 may preferably be about 60% to about 85%.

The conductor density of the portion of the inner electrode layer 4included in the width-direction first end portion region 9 d 1, theconductor density of the portion of the inner electrode layer 4 includedin the width-direction second end portion region 9 d 2, and theconductor density of the portion of the inner electrode layer 4 includedin the width-direction center portion region 9 c can be measured by themeasuring method using the electron microscope described in the firstpreferred embodiment. More specifically, the measurement can beperformed by setting the cross-section to be exposed during grinding ata cross-section including the width-direction first end portion region 9d 1, a cross-section including the width-direction center portion region9 c, and a cross-section including the width-direction second endportion region 9 d 2, or at a cross-section collectively including thewidth-direction first end portion region 9 d 1, the width-directioncenter portion region 9 c, and the width-direction second end portionregion 9 d 2.

An example of a non-limiting method of causing the conductor density inthe width-direction first end portion region 9 d 1 and the conductordensity in the width-direction second end portion region 9 d 2 to belower than the conductor density in the width-direction center portionregion 9 c is described below. FIG. 15 is an exploded view showing amultilayer structure of an element body included in the monolithicceramic capacitor shown in FIG. 12.

As shown in FIG. 15, the element body 2 is manufactured using a materialsheet group 10D as a material including a plurality of material sheets11A, 11E1, and 11E2 with different configurations. More specifically,the element body 2 is manufactured by stacking the plurality of materialsheets 11A, 11E1, and 11E2 with the different configurations in apredetermined order, press-bonding the material sheets, and firing thematerial sheets.

The material sheet 11A is formed of only a ceramic base and does notinclude a conductive pattern provided on its surface. The material sheet11A becomes the ceramic dielectric layer 3 of a portion that defines thethickness-direction first outer layer portion 6 b 1 or thethickness-direction second outer layer portion 6 b 2 after firing.

The material sheets 11E1 and 11E2 each include conductive patterns 13 aand 13 b having predetermined shapes on a surface of a ceramic base 12.The conductive pattern 13 a is a conductive pattern of a portion that isincluded primarily in the width-direction center portion region 9 cafter firing, and is strip-shaped or substantially strip shaped so as toextend in the length direction L in the center portion in the widthdirection W. The conductive pattern 13 b is a conductive pattern of aportion that is included primarily in the width-direction first endportion region 9 d 1 and the width-direction second end portion region 9d 2 after firing, and is strip-shaped substantially strip shaped so asto extend in the length direction L at both end portions in the widthdirection W. Also, the ceramic base 12 of each of the material sheets11E1 and 11E2 becomes the ceramic dielectric layer 3 of a portion thatdefines the thickness-direction inner layer portion 6 a or thethickness-direction second outer layer portion 6 b 2 after firing.

Similarly to the first preferred embodiment, the above-describedconductive patterns 13 a and 13 b are preferably configured to havedifferent thicknesses by adjusting the amount of conductor paste to beapplied to the ceramic bases 12. Accordingly, the conductor density inthe width-direction first end portion region 9 d 1 and the conductordensity in the width-direction second end portion region 9 d 2 are lowerthan the conductor density in the width-direction center portion region9 c during firing.

As described above, in the monolithic ceramic capacitor 1D according tothis preferred embodiment, since the conductor density in thewidth-direction first end portion region 9 d 1 and the conductor densityin the width-direction second end portion region 9 d 2 are lower thanthe conductor density in the width-direction center portion region 9 c,the capacity of the monolithic ceramic capacitor is increased while theoccurrence of delamination is effectively reduced. Accordingly, thereliability of the product is increased, and the yield of themanufacturing process is prevented from being decreased.

Fourth Preferred Embodiment

FIG. 16 is an exploded view showing a multilayer structure of an elementbody included in a monolithic ceramic capacitor according to a fourthpreferred embodiment of the present invention. Next, a configuration ofa monolithic ceramic capacitor 1E according to this preferred embodimentis described with reference to FIG. 16.

As shown in FIG. 16, the monolithic ceramic capacitor 1E according tothis preferred embodiment is a combination of the characteristicconfigurations described in the second and third preferred embodiments.

That is, the monolithic ceramic capacitor 1E according to this preferredembodiment is configured such that the conductor density in thelength-direction first end portion region 9 b 1 located at the first endsurface 2 b 1 side in the multilayer portion 9 and the conductor densityin the length-direction second end portion region 9 b 2 located at thesecond end surface 2 b 2 side in the multilayer portion 9 are bothpreferably lower than the conductor density in the residual region inthe multilayer portion 9, that is, the length-direction center portionregion 9 a located at the center in the length direction L in themultilayer portion 9; and the conductor density in the width-directionfirst end portion region 9 d 1 located at the first side surface 2 c 1side in the multilayer portion 9 and the conductor density in thewidth-direction second end portion region 9 d 2 located at the secondside surface 2 c 2 side in the multilayer portion 9 are both preferablylower than the conductor density in the residual portion in themultilayer portion 9, that is, the width-direction center portion region9 c located at the center in the width direction W in the multilayerportion 9.

The monolithic ceramic capacitor 1E with this configuration preferablyis provided by including a multilayer structure of material sheets asshown in FIG. 16.

As shown in FIG. 16, the element body 2 is manufactured preferably usinga material sheet group 10E as a material including a plurality ofmaterial sheets 11A, 11F1, and 11F2 with different configurations. Morespecifically, the element body 2 is manufactured by stacking theplurality of material sheets 11A, 11F1, and 11F2 with the differentconfigurations in a predetermined order, press-bonding the materialsheets, and firing the material sheets.

The material sheet 11A preferably includes only a ceramic base 12 anddoes not include a conductive pattern on its surface. The material sheet11A becomes the ceramic dielectric layer 3 of a portion that defines thethickness-direction first outer layer portion 6 b 1 or thethickness-direction second outer layer portion 6 b 2 after firing.

The material sheets 11F1 and 11F2 each include conductive patterns 13 aand 13 b having predetermined shapes on a surface of a ceramic base 12.The conductive pattern 13 a with the large thickness becomes theabove-described portion of the inner electrode layer 4 with therelatively high conductor density, and is strip-shaped or substantiallystrip shaped so as to extend in the length direction L. Also, theconductive pattern 13 b with the small thickness becomes theabove-described portion of the inner electrode layer 4 with therelatively low conductor density, and is provided to surround one endportion in the length direction L and both end portions in the widthdirection W of the conductive pattern 13 a. Also, the ceramic base 12 ofeach of the material sheets 11F1 and 11F2 becomes the ceramic dielectriclayer 3 of the portion that defines the thickness-direction inner layerportion 6 a or the thickness-direction second outer layer portion 6 b 2after firing.

With this configuration, in the monolithic ceramic capacitor 1Eaccording to this preferred embodiment, the capacity of the monolithicceramic capacitor is increased while the occurrence of delamination,which starts at the surface of the multilayer portion 9 located in thelength direction L and the width direction W, is effectively reduced.Accordingly, the reliability of the product is increased, and the yieldof the manufacturing process is effectively prevented from beingdecreased.

Fifth Preferred Embodiment

FIG. 17 is an exploded view showing a multilayer structure of an elementbody included in a monolithic ceramic capacitor according to a fifthpreferred embodiment of the present invention. Next, a configuration ofa monolithic ceramic capacitor 1F according to this preferred embodimentis described with reference to FIG. 17.

As shown in FIG. 17, the monolithic ceramic capacitor 1F according tothis preferred embodiment is a combination of the characteristicconfigurations described in the aforementioned first and fourthpreferred embodiments.

That is, the monolithic ceramic capacitor 1F according to this preferredembodiment is configured such that the conductor densities of the firstoutermost layer 4 a and the second outermost layer 4 b are lower thanthe conductor density of any inner electrode layer 4 located between thefirst outermost layer 4 a and the second outermost layer 4 b; theconductor density in the length-direction first end portion region 9 b 1located at the first end surface 2 b 1 side in the multilayer portion 9and the conductor density in the length-direction second end portionregion 9 b 2 located at the second end surface 2 b 2 side in themultilayer portion 9 are lower than the conductor density in theresidual region in the multilayer portion 9, that is, thelength-direction center portion region 9 a located at the center in thelength direction L in the multilayer portion 9; and the conductordensity in the width-direction first end portion region 9 d 1 located atthe first side surface 2 c 1 side in the multilayer portion 9 and theconductor density in the width-direction second end portion region 9 d 2located at the second side surface 2 c 2 side in the multilayer portion9 are lower than the conductor density in the residual region in themultilayer portion 9, that is, the width-direction center portion region9 c located at the center in the width direction W in the multilayerportion 9.

The monolithic ceramic capacitor 1F with this configuration preferablyincludes a multilayer structure of material sheets as shown in FIG. 17.

As shown in FIG. 17, the element body 2 is manufactured preferably usinga material sheet group 10F as a material including a plurality ofmaterial sheets 11A, 11C1, 11C2, 11F1, and 11F2 with differentconfigurations. More specifically, the element body 2 is manufactured bystacking the plurality of material sheets 11A, 11C1, 11C2, 11F1, and11F2 with the different configurations in a predetermined order,press-bonding the material sheets, and firing the material sheets. Theconfigurations of the plurality of material sheets 11A, 11C1, 11C2,11F1, and 11F2 are described above, and the description is not repeatedhere.

With this configuration, in the monolithic ceramic capacitor 1Faccording to this preferred embodiment, the delamination at the surfaceof the multilayer portion 9 located in the thickness direction T isprevented from occurring, the occurrence of delamination, which startsat the surface of the multilayer portion 9 located in the lengthdirection L and the width direction W, is effectively reduced, and thecapacity of the monolithic ceramic capacitor is increased. Accordingly,the reliability of the product is increased, and the yield of themanufacturing process is effectively prevented from being decreased.

In the monolithic ceramic capacitor 1F according to this preferredembodiment, the conductor densities of the first outermost layer 4 a andthe second outermost layer 4 b are preferably lower than the conductordensity in the length-direction first end portion region 9 b 1 locatedat the first end surface 2 b 1 side in the multilayer portion 9, theconductor density in the length-direction second end portion region 9 b2 located at the second end surface 2 b 2 side in the multilayer portion9, the conductor density in the width-direction first end portion region9 d 1 located at the first side surface 2 c 1 side in the multilayerportion 9, and the conductor density in the width-direction second endportion region 9 d 2 located at the second side surface 2 c 2 side inthe multilayer portion 9.

This is because separation caused by a difference in contraction ratiobetween a dielectric layer and a conductor layer during firing morelikely occurs at a side at which the thickness-direction first outerlayer portion 6 b 1 and the thickness-direction second outer layerportion 6 b 2 are located, as compared to a side at which thelength-direction first outer layer portion 7 b 1, the length-directionsecond outer layer portion 7 b 2, the width-direction first outer layerportion 8 b 1, and the width-direction second outer layer portion 8 b 2are located, when viewed from the multilayer portion 9. In particular,if the conductor densities of the first outermost layer 4 a and thesecond outermost layer 4 b are decreased, the fixing force between thefirst outermost layer 4 a and the thickness-direction first outer layerportion 6 b 1 and the fixing force between the second outermost layer 4b and the thickness-direction second outer layer portion 6 b 2 areincreased. Thus, the effect of the increase in reliability and yieldbecomes more apparent.

The conductor densities of the first outermost layer 4 a and the secondoutermost layer 4 b are preferably lower than the conductor densities inthe length-direction first end portion region 9 b 1, thelength-direction second end portion region 9 b 2, the width-directionfirst end portion region 9 d 1, and the width-direction second endportion region 9 d 2, by about 10%, for example. If the conductordensities of the first outermost layer 4 a and the second outermostlayer 4 b are extremely lowered beyond the above-described preferredrange, the situation becomes equal or substantially equal to a situationin which the first outermost layer 4 a or the second outermost layer 4 bdoes not exist. Thus, the separation may additionally occur between theinner electrode layer 4 and the dielectric layer located at a positionclosest to each of the first outermost layer 4 a and the secondoutermost layer 4 b.

A result of a verification test is described next, in which a prototypeof the monolithic ceramic capacitor 1F according to this preferredembodiment was actually manufactured and it was verified whether or notdelamination occurs.

In the verification test, as an example, 20 monolithic ceramiccapacitors were manufactured, each of the monolithic ceramic capacitorsincluding an element body having design values of the size of 1.0 mmlength, 0.5 mm width, and 0.5 mm thickness. In each monolithic ceramiccapacitor according to the example, a design value of the distancebetween the inner electrode layers (that is, the thickness of thedielectric layer) was 1.0 μm, a design value of the thickness of theinner electrode layer was 1.0 μm, the number of stacked inner electrodelayers was 350, a design value of the thickness of the sintered metallayer of the outer electrode was 28 μm, and design values of thethicknesses of the Ni-plated layer and Sn-plated layer of the outerelectrode were each 3 μm.

Also, in the monolithic ceramic capacitor according to the example, thegravure printing method was used, and the conductive pattern 13 a with alarge thickness and the conductive pattern 13 b with a small thicknesswere printed on the ceramic bases 12 according to the layout as shown inFIG. 17. Accordingly, in the monolithic ceramic capacitor according tothe example, by executing the firing step, the conductor density of theportion of the inner electrode layer corresponding to the conductivepattern 13 b with the small thickness was lower than the conductordensity of the portion of the inner electrode layer corresponding to theconductive pattern 13 a with the large thickness by about 5% to about10%.

In contrast, as a comparative example, 20 monolithic ceramic capacitorswere manufactured. Each monolithic ceramic capacitor was formed suchthat the thickness of all conductive patterns was equal or substantiallyequal to the thickness of the conductive pattern 13 a according to theexample. The manufacturing condition of the monolithic ceramic capacitoraccording to the comparative example was the same or substantially thesame as the manufacturing condition of the monolithic ceramic capacitoraccording to the example, except that the aforementioned thicknesses ofthe conductive patterns were uniformly large. Accordingly, with themonolithic ceramic capacitor according to the comparative example, theinner electrode layer formed in the firing step had an equivalentconductor density in the entire region.

In the monolithic ceramic capacitor according to the example (that is,in the monolithic ceramic capacitor designed such that the conductordensity at an outer edge portion of the multilayer body was partly low),the occurrence of delamination was not observed in any of themanufactured 20 monolithic ceramic capacitors, and in the monolithicceramic capacitor according to the comparative example (that is, in themonolithic ceramic capacitor designed such that the conductor densitywas uniform in the entire region of the multilayer body), thedelamination occurred in one of the 20 manufactured monolithic ceramiccapacitors.

The conductor densities were measured by a process according to theprocess described in the aforementioned first to third preferredembodiments for all monolithic ceramic capacitors according to theexample and all monolithic ceramic capacitors according to thecomparative example. As the result, it was ensured that the conductordensities of the respective portions were designed values.

As is clear from this result, by using the monolithic ceramic capacitorsaccording to the example, the effective reduction in occurrence ofdelamination was experimentally ensured.

In the preferred embodiments of the present invention described above,the combination of the characteristic configurations described in theaforementioned second and third preferred embodiments has beenexemplarily described as the fourth preferred embodiment, and thecombination of the characteristic configurations described in theaforementioned first to third preferred embodiments has been exemplarilydescribed as the fifth preferred embodiment. However, a combination ofother residual characteristic configurations including thecharacteristic configuration described in the modification based on theabove-described first preferred embodiment may also be used.

The above-described preferred embodiments and modification currentlydisclosed are merely examples, and are not intended to be limited. Thetechnical scope of the present invention is defined by the claims andincludes meaning equivalent to the description of the claims and allmodifications within the scope.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

What is claimed is:
 1. A monolithic ceramic capacitor comprising: anelement body including a multilayer portion including a plurality ofconductor layers and a plurality of ceramic dielectric layersalternately stacked in a thickness direction of the element body; and anouter electrode provided on an outer portion of the element body;wherein outer surfaces of the element body include a first principalsurface and a second principal surface that are opposed to each other inthe thickness direction, a first end surface and a second end surfacethat are opposed to each other in a length direction perpendicular orsubstantially perpendicular to the thickness direction, and a first sidesurface and a second side surface that are opposed to each other in awidth direction perpendicular or substantially perpendicular to both thethickness direction and the length direction; the element body isdivided in the thickness direction into a thickness-direction firstouter layer portion that includes a first ceramic dielectric layer anddefines the first principal surface, a thickness-direction second outerlayer portion that includes a second ceramic dielectric layer anddefines the second principal surface, and a thickness-direction innerlayer portion including the multilayer portion and located between thethickness-direction first outer layer portion and thethickness-direction second outer layer portion; among the plurality ofconductor layers included in the thickness-direction inner layerportion, a first conductor layer arranged at a position closest to thefirst principal surface is provided at a position adjacent to the firstceramic dielectric layer of the thickness-direction first outer layerportion; among the plurality of conductor layers included in thethickness-direction inner layer portion, a second conductor layerarranged at a position closest to the second principal surface isprovided at a position adjacent to the second ceramic dielectric layerof the thickness-direction second outer layer portion; the outerelectrode includes a first outer electrode provided to cover the firstend surface, and a second outer electrode provided to cover the secondend surface; one portion of the plurality of conductor layers isconnected to the first outer electrode through a first wiring portionextending from the multilayer portion toward the first end surface side;another portion of the plurality of conductor layers is connected to thesecond outer electrode through a second wiring portion extending fromthe multilayer portion toward the second end surface side; the elementbody is divided in the length direction into a length-direction firstouter layer portion that includes portions of the conductor layer andthe ceramic dielectric layer corresponding to the first wiring portionand defines the first end surface, a length-direction second outer layerportion that includes portions of the conductor layer and the ceramicdielectric layer corresponding to the second wiring portion and definesthe second end surface, and a length-direction inner layer portion thatincludes the multilayer portion and is located between thelength-direction first outer layer portion and the length-directionsecond outer layer portion; a conductor density in a length-directionfirst end portion region located at the first end surface side in themultilayer portion, and a conductor density in a length-direction secondend portion region located at the second end surface side in themultilayer portion are lower than a conductor density in alength-direction center portion region located at a center in the lengthdirection in the multilayer portion; the element body is divided in thewidth direction into a width-direction first outer layer portion thatincludes the ceramic dielectric layer and defines the first sidesurface, a width-direction second outer layer portion that includes theceramic dielectric layer and defines the second side surface, and awidth-direction inner layer portion that includes the multilayer portionand is located between the width-direction first outer layer portion andthe width-direction second outer layer portion; a conductor density in awidth-direction first end portion region located at the first sidesurface side in the multilayer portion, and a conductor density in awidth-direction second end portion region located at the second sidesurface side in the multilayer portion are lower than a conductordensity in a width-direction center portion region located at the centerin the width direction in the multilayer portion; and the conductordensities of the first conductor layer and the second conductor layerare lower than the conductor densities in the length-direction first endportion region, the length-direction second end portion region, thewidth-direction first end portion region, and the width-direction secondend portion region.
 2. The monolithic ceramic capacitor according toclaim 1, wherein the first conductor layer and the second conductorlayer each include a plurality of fine through holes penetrating throughthe first conductor layer and the second conductor layer in thethickness direction; and the plurality of through holes are filled witha ceramic dielectric material.
 3. The monolithic ceramic capacitoraccording to claim 1, wherein a portion of the conductor layer connectedto the second outer electrode and included in the length-direction firstend portion region among the plurality of conductor layers, and aportion of the conductor layer connected with the first outer electrodeand included in the length-direction second end portion region among theplurality of conductor layers include a plurality of fine through holespenetrating through the portions of the conductor layers in thethickness direction; and the plurality of through holes are filled withthe ceramic dielectric material.
 4. The monolithic ceramic capacitoraccording to claim 1, wherein portions included in the width-directionfirst end portion region and the width-direction second end portionregion among the plurality of conductor layers include a plurality ofthrough holes penetrating through the conductor layers in the thicknessdirection; and the plurality of through holes are filled with theceramic dielectric material.
 5. The monolithic ceramic capacitoraccording to claim 1, wherein the first conductor layer and the secondconductor layer are floating conductor layers not connected with theouter electrode.
 6. The monolithic ceramic capacitor according to claim1, wherein the element body has a rectangular or substantiallyrectangular parallelepiped shape.
 7. The monolithic ceramic capacitoraccording to claim 1, wherein the plurality of ceramic dielectric layersinclude barium titanate.
 8. The monolithic ceramic capacitor accordingto claim 7, wherein the plurality of ceramic dielectric layers furtherinclude at least one of a Mn compound, a Mg compound, a Si compound, aCo compound, a Ni compound, and a rare-earth compound.
 9. The monolithicceramic capacitor according to claim 1, wherein the plurality ofconductor layers are made of Ni or Cu.
 10. The monolithic ceramiccapacitor according to claim 1, wherein the outer electrode is definedby a multilayer film.
 11. The monolithic ceramic capacitor according toclaim 10, wherein the multilayer film includes a sintered metal layerdisposed on the outer portion of the element body and a plated layerdisposed on the sintered metal layer.
 12. The monolithic ceramiccapacitor according to claim 11, wherein the sintered metal layer ismade of a sintered conductor paste including at least one of Cu, Ni, Ag,Pd, an Ag—Pd alloy, and Au.
 13. The monolithic ceramic capacitoraccording to claim 11, wherein the plated layer is one of a Cu platedlayer and an Au plated layer.
 14. The monolithic ceramic capacitoraccording to claim 1, wherein a thickness of the first conductor layerand the second conductor layer is smaller than a thickness of the otherconductor layer located between the first and second conductor layers.15. The monolithic ceramic capacitor according to claim 1, wherein edgeportions and corner portions of the element body are rounded.